Rangers manager Derek McInnes has been speaking with the media before the trip to face Old Firm rivals Celtic in the Premiership on Sunday (12:00 BST). McInnes confirmed the club have spoken with SFA head of referees Willie Collum about Mika Baur's challenge on Ryan Naderi last weekend that has left the German striker as a doubt for Sunday. Tuur Rommens trained after injury and may be available.